The present invention relates to a communication platform LSI for converting general information data, transmitted through a general purpose information system network such as a communication network based on Ethernet or ISDN (integrated services digital network) into control data such as data from a sensor or an actuator transmitted through a dedicated control system network for centrally controlling facilities in scattered buildings at a distant place, or vice versa and for executing communication between those different kind of data.
The present invention also relates to a communication platform LSI used in the above system, and a communication control. method in the above system.
Conventionally, exchanging (communicating or negotiating) of information data from Ethernet, ISDN, or IrDA (infrared data association) with control data from digital I/O or counter I/O used for sensor monitoring has not been considered so much. Conventionally, in order to exchange the control data with the information data on a high-speed communication protocol of Ethernet or ISDN, control data is once converted to a protocol for a distributed control system network such as a LON (local operating network) or a protocol for an ISA bus and then it is converted to an information system communication protocol such as TCP/IP or Ethernet again. As stated above, direct exchange between the control data such as those used for executing sensor monitoring or actuator drive controlling with the information data based on high-speed communication protocol of Ethernet or ISDN is not considered so much. As a result, the exchange has been realized by converting the protocol several times and a problem arises that the system for that purpose becomes complex and large in scale.
Furthermore, by connecting an information system network represented by Ethernet or ISDN with a control system network represented by LON, the control system network limited to a small area can be extended to a large scale network as a whole. In such a system, for example, to constitute a device for connecting between networks, a plurality of different communication LSIs are used depending on the kind of each network or separate LSIs are used so as to control the device from each control network are used.
For example, with recent development of the communication art, various type of networks are formed and operated. Among them, there is a control system network. This control system network is applied to, for example, a building management system and a plant management system. As shown in FIG. 1, this control system network is installed to exchange control data between control nodes 20 and a control device 10 for centrally managing the control nodes 20. Control nodes 20 is provided for executing monitoring and drive controlling of a sensor 30 and actuators (an illumination 31, a switch 32, a motor 33, a braker 34, and an alarm 35).
This control system network 1 has a sole function of sending and receiving control data between the control nodes 20 and the control device 10. A dedicated communication protocol is, therefore, used which is suited to the control system network 1, such as Lon Talk developed by Echelon Corporation in USA. Each control node 20 used in the control system network 1 using this Lon Talk is atone-chip electronic circuit. In the circuit, a CPU 21, a memory 22, a control input/output port 24, and a LON controller 25 are connected via a bus 23 as shown in FIG. 2. When control data sent on a LON network (a network for sending and receiving data by Lon Talk), a control system network, is supplied to the circuit via a LON controller (a communication controller for connecting to the LON network) 25, the CPU 21 refers to the program which is stored in the memory 22 and whose execution is controlled by CPU 21, and generates a control signal for controlling the drive of various actuators corresponding to the control data. The circuit also outputs the control signal via the control input/output port 24 when detection signals from various sensors are supplied via the control input/output port 24, the CPU 21 refers to the program which is stored in the memory 22 and whose execution is controlled by CPU 21, and generates control data indicating the detection contents. The circuit sends it to the LON network via the LON controller 25. Namely, with this control system network 1, a centralized management system can be easily constructed only by describing (programming) the function to be executed by each control node 20. The control system network is, therefore, rapidly spreading recently.
As mentioned above, conventionally, it is not considered so much to send and receive data of the information system of Ethernet, ISDN, or IrDA and data of the control system of digital I/O or counter I/O used for sensor monitoring. Directly sending or receiving control data used when executing sensor monitoring or actuator drive control with an information system high-speed communication protocol of Ethernet or ISDN is not considered so much. As a result, the aforementioned sending and receiving are realized by converting the protocol several times and a problem arises that the system for that purpose becomes complex and large in scale. Furthermore, since the system is connected to a plurality of kinds of networks, when a special LSI is developed for each network, many kinds of LSIs are necessary, and the development efficiency gets worse, and the mass production effect cannot be expected, and an increase in cost is caused.
As indicated in Japanese Patent Application Laid-Open 7-30981 which is a Japanese application patent, there is a system having a means for constructing a network memory on an information system LAN and writing data required by the information system in the network memory on the information system LAN by using data in a network memory on a control system LAN. However, this patent application neither discloses nor suggests any concrete idea of resolving the above problems.
In the aforementioned control system network, it is supposed to send and receive control data via a communication controller only for the control system network such as the LON controller 25 shown in FIG. 2. It means that the control system network is independent of other general purpose networks (information system networks). On the other hand, there is a recently increasing need for constructing a large scale network including control system networks such as a request for constructing a large scale centralized management system by connecting a plurality of control system networks such as mentioned above. Generally, when constructing a large scale network by connecting a plurality of networks, a computer for controlling those networks is necessary. In the world of information system network, there are standard protocols including Ethernet, so that to execute efficient network control by a computer, it is desirable to use a standard protocol such as Ethernet.
However, as mentioned above, a control system network using a dedicated communication protocol such as Lon Talk is independent of other general purpose networks because a centralized management system can be easily constructed and is not a network for which mutual connection with other networks is taken into account. A problem, therefore, arises that it is difficult to construct a large scale network including control system networks. Furthermore, when developing gateway LSIs for connecting these control system networks to information system networks, it is forced to develop a plurality of kinds of LSIs according to the protocols of information system networks on the remote side. Thus a problem arises that the development efficiency is low and the mass production effect cannot be expected.
An object of the present invention is to eliminate the aforementioned failures.
Another object of the present invention is to provide a communication platform LSI system for easily realizing mutual exchange (communication/negotiation) of control system data and information system data. The object is fulfilled by mounting a control system I/O interface for executing sensor monitoring and actuator drive control, an information system communication interface of Ethernet or others, and a data conversion CPU on one chip.
Yet another object of the present invention is to provide a communication platform LSI used in the system, and a control method for communication in the system.
The communication platform LSI of the present invention is a communication platform LSI for executing communication by converting information system data from a communication network of Ethernet or ISDN and control system data of a LON network which is an autonomous distributed control network or of digital I/O or counter I/O used for sensor monitoring to data which can be mutually exchanged, which includes a storage means for storing the information system data and control system data, an information system data communication control means for controlling sending and receiving of data to and from the communication network, a control system data interface means for controlling sending and receiving of data to and from the sensor, and a conversion means for reading and writing data sent and received by the information system data communication control means and by the control system data interface means from and into the storage means and converting the protocol of the data to a protocol suited to the protocol of the sending destination, wherein when sending the information system data received from the communication network to the sensor, the protocol conversion means stores the information system data received by the information system data communication control means in the storage means, converts the protocol of the stored information system data to data capable of controlling the sensor, and stores it in the storage means, and the control system data interface means sends the protocol-converted data in the storage means to the sensor, and wherein when sending the control system data received from the sensor to the communication network, the protocol conversion means stores the control system data received by the control system data interface means in the storage means, converts the protocol of the stored control system data to a protocol suited to the communication network, and stores it in the storage means, and the information system data communication control means sends the protocol-converted data in the storage means to the communication network.
According to the present invention described above, mutual communication by control system data from a sensor or actuator and by information system data from a communication network based on Ethernet or ISDN can be simply realized. To correspond to a plurality of sensors, a plurality of aforementioned control system data interface means may be installed in correspondence to each sensor. A plurality of aforementioned information system data communication control means may be installed so as to correspond to a plurality of communication protocols.
Furthermore, for example, speaking of a factory including a communication platform LSI according to the present invention, when a plurality of blocks (each block corresponds to one line or one building) are installed and the blocks are controlled by a computer via the aforementioned communication network, data supplied from the blocks can be centrally managed by gathering them. Thus the system in which each block is installed can be made smaller and showing another system example using the communication platform LSI of the second embodiment.